Diagnostic utility of FDG PET in multiple myeloma

OBJECTIVE: Very little information is available regarding the diagnostic utility of positron emission tomography with [(18)F]fluorodeoxyglucose (FDG PET) in multiple myeloma. Our objective was to further define the role of FDG PET in the clinical assessment of patients with multiple myeloma. DESIGN AND PATIENTS: Nine whole-body PET scans (45 min after intravenous administration of 370-555 MBq FDG) were performed in six patients (age 38-62 years, 5 males) with multiple myeloma for evaluation of the extent of disease at the time of initial diagnosis (n=3) and for assessment of therapy response (n=3). Three patients had PET scans both before and after therapy. Prior treatments included chemoradiation therapy (n=2) and chemotherapy with autologous bone marrow transplantation (n=1). Correlative imaging data were available in all patients and included skeletal radiographic survey (n=6), bone scan (n=3), and spinal CT or MRI (n=4), and were all obtained within 3 months of the PET study. Validation was by clinical or imaging follow-up. RESULTS: In three patients with both pre- and post-therapy PET scans, PET demonstrated a favorable treatment response, by showing a decline in lesion metabolic activity (n=1), or progression of disease, by showing development of new lesions or higher lesion glucose metabolism (n=2), concordant with the clinical evaluation, while the other imaging studies showed no discernible interval changes. PET detected multiple hypermetabolic lesions in one patient with a negative bone scan and concordant positive skeletal radiographic survey. Bone scans underestimated the extent of disease in two other patients in comparison with PET. PET also detected a few early marrow lesions with subtle radiographic changes while all radiographically aggressive lytic lesions corresponded to intense hypermetabolism on PET. CONCLUSION: PET can detect early marrow involvement of multiple myeloma and is useful in assessing the extent of active disease at the time of initial presentation and in evaluating treatment response.     

Therapy assessment in multiple myeloma with PET

Multiple myeloma is a plasma cell dyscrasia producing bone lytic lesions. In recent years, a wide spectrum of therapeutic approaches are available to treat the disease: an accurate therapy assessment has, therefore, become of utmost importance. In this field, imaging is becoming a cornerstone, especially in association with clinical parameters. Among imaging procedures, FDG PET/CT is recognized to provide reliable information, achieved in a very safe and fast procedure.  The literature has produced very concordant results from different groups assessing the value of FDG PET/CT as a prognostic factor in general and in therapy assessment, but some issues remain regarding a standardization of image interpretation especially in borderline cases. So far, no data regarding nor other imaging compounds and the use of hybrid tomographs PET/MR are available to define therapy assessment in PET.     

The value of FDG PET/CT in the initial staging and bone marrow involvement of patients with multiple myeloma

Objective  

The aim of this study was to describe the role of positron emission tomography/computed tomography (PET/CT) with fluorine-18 fluorodeoxyglucose (FDG) in the detection of skeletal and visceral involvement in patients with MM (multiple myeloma) at the initial diagnosis and to evaluate the relation between maximum standardized uptake values (SUVmax) of FDG with bone marrow cellularity and plasma cell ratios.     

Value of FDG PET in patients with fever of unknown origin.

Fever of unknown origin (FUO) is a diagnostic challenge, because the cause of such fever may be manifold. Studies on the use of positron emission tomography (PET) using 18F-fluorodeoxyglucose (18F-FDG), for the diagnosis of inflammation in patients with osteomyelitis or HIV have been promising and suggest its use in patients with FUO. In this study, we used FDG PET in 16 patients with FUO in whom conventional diagnostics had not been conclusive. In 12 patients, (75%) non-physiological accumulations of FDG were found which led to the final diagnosis in 11 patients (69%). FDG PET was negative in four patients (25%). Two of these patients had rheumatic fever, while in the other two patients the origin of fever could not be detected within 3 months after PET by any other laboratory or imaging means. These findings point to the high sensitivity of FDG whole-body PET for the detection of morphologically assessable foci as an origin of FUO. Moreover, they suggest a high negative predictive value of FDG PET in the setting of FUO, since in no patient with a negative FDG PET could a morphological origin of the fever be determined. In conclusion, FDG whole-body PET appears to be a promising diagnostic tool in patients with FUO, in whom conventional diagnostics had been unsuccessful.     

F-18 FDG PET/CT staging of multiple myeloma with diffuse osseous and extramedullary lesions

Multiple myeloma is the most common plasma cell neoplasm, with abnormal clonal proliferation of B cells in bone marrow. Its staging is important for therapeutic management and prognosis. F-18 FDG PET/CT is of proven value in staging and posttherapeutic monitoring multiple myeloma. Through imaging integration, PET provides functional detection of high metabolic lesions whereas CT provides correlated anatomic localization. The authors present a case of multiple myeloma status post chemotherapy and stem cell transplant with diffuse osseous and extramedullary lesions evaluated by PET/CT. The extramedullary involvement concerns the maxillary sinus, thyroid cartilage, mediastinum, retroperitoneum, neuroforamen, and epidura.     

Initial results in the assessment of multiple myeloma using 18F-FDG PET

This prospective study was undertaken to investigate the appearance of multiple myeloma on fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET). Furthermore, the accuracy of FDG-PET in detecting myeloma lesions and its influence on patient management were evaluated. Forty-three patients with known multiple myeloma (n=28) or solitary plasmacytoma (n=15) underwent FDG-PET. The results of routinely performed radiographs and of scans obtained using all available imaging modalities (MRI, CT), as well as the clinical course, were used for verification of detected lesions. Focally increased tracer uptake was observed in 38 of 41 known osteolytic bone lesions (sensitivity 92.7%) in 23 patients. In addition, 71 further bone lesions which were negative on radiographs were detected in 14 patients. Twenty-six (36.6%) of these lesions could be confirmed in ten patients. As a result of FDG-PET imaging, clinical management was influenced in five (14.0%) patients. The positive predictive value for active disease was 100% in patients with focal or mixed focal/diffuse skeletal FDG uptake and 75% in patients with diffuse bone marrow uptake. Depending on the interpretation of the PET scans in patients with diffuse bone marrow uptake, the sensitivity ranged from 83.8% to 91.9% and the specificity from 83.3% to 100%. FDG-PET thus proved highly accurate in detecting multiple myeloma, and revealed a greater extent of disease than routine radiographs in 14 of 23 (60.9%) patients who had osteolytic bone lesions. FDG-PET might contribute to the initial staging of solitary plasmacytoma.     

Risk assessment in liposarcoma patients based on FDG PET imaging

Purpose Tumor grade and subtype are considered standard parameters for risk assessment in patients with liposarcoma. The aim of this study was to assess the clinical value of [¹⁸F]fluorodeoxyglucose (FDG) PET-derived maximum standardized uptake value (SUV_max) for prediction of outcome in liposarcoma patients.Methods ¹⁸F-FDG PET was performed in 54 patients with liposarcoma prior to therapy. SUV_max was calculated for each tumor and results were correlated with tumor grade, subtype, and relapse-free survival.Results SUV_max ranged from 0.4 to 15.9 (mean 3.6) and was significantly lower in grade I than in grade II and grade III tumors. SUV_max was 2.3±1.7, 3.5±1.5, 4.8±2.5, and 5.6±5.8 in well-differentiated, myxoid/round cell, dedifferentiated, and pleomorphic subtypes, respectively. Borderline differences (p=0.059) were found between tumor SUV_max in patients with and without relapse. Using a SUV of 3.6 as cut-off, the accuracy in predicting a relapse was 75%. Tumor grade yielded a lower accuracy for predicting relapse (50%), as did tumor subtype (35%). In Kaplan-Meier survival analysis, patients with a SUV_max >3.6 had a significantly shorter disease-free survival of 21 months compared with 44 months in patients with a SUV_max ≤3.6. Tumor grading and tumor subtype did not yield significant differences.Conclusion Pretherapy tumor SUV obtained by FDG PET imaging was a more useful parameter for risk assessment in liposarcoma than tumor grade or subtype. A SUV_max of more than 3.6 resulted in a significantly reduced disease-free survival and identified patients at high risk for developing early local recurrences or metastatic disease.     

F-18 FDG whole-body PET for the assessment of disease activity in patients with rheumatoid arthritis

PURPOSE OF REPORT: F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) can be used to image synovitis in patients with rheumatoid arthritis (RA). The aim of this study was to evaluate if a simple scoring system based on visual assessment of FDG joint uptake correlates with the clinical assessment of patients with RA undergoing antiinflammatory treatment. MATERIALS AND METHODS: Seven patients with active RA underwent whole-body FDG PET and clinical assessment before and after treatment with the antitumor necrosis factor alpha antibody (infliximab). A PET total joint score, ie, the sum of all scores based on FDG uptake intensity between zero and 4 in 28 joints, was correlated with a total joint score based on the clinical disease activity in the same joints using a Spearman rank correlation. RESULTS: The PET based total joint score was similarly high before onset as was the clinical total joint score. The decrease of FDG joint uptake in the follow-up PET scans correlated significantly with the clinical assessment. Additionally, synovial FDG uptake was found in extraarticular sites such as tendon sheaths and bursae. CONCLUSIONS: Visual assessment of FDG uptake shows a significant correlation with clinical evaluation of disease activity in patients with RA undergoing antiinflammatory treatment.     

FDG PET/CT in patients with HIV

OBJECTIVE: This article will discuss the (18)F-FDG normal variant uptake and the role of FDG PET/CT in malignancies in HIV-infected patients, CNS manifestations of HIV, assessing fever of unknown origin in HIV patients, assessing response to highly active antiretroviral therapy and assessing complications. CONCLUSION: FDG PET/CT is a valuable imaging study in the management of HIV-infected patients.     

Comparison of imaging with FDG PET/CT with other imaging modalities in myeloma

Objective To determine the usefulness of FDG PET/CT scanning in the management and staging of myeloma and to assess its strengths and limitations.Design FDG PET/CT scans and all other available imaging studies were reviewed retrospectively from 16 consecutive patients by two experienced musculoskeletal radiologists and two nuclear medicine physicians working in consensus.Patients The 16 patients had undergone a total of 19 FDG PET/CT scans. Radiographs were available in all cases, including 13 skeletal surveys; 25 CT scans (16 chest, three abdominal, four pelvic, one spine, one neck) and 22 MR imaging studies (17 spine, three pelvic, two extremity) also were reviewed. Patients’ records were examined for relevant clinical information. All focal areas of abnormal FDG uptake were correlated with the other imaging studies to determine clinical significance. FDG PET/CT scans also were reviewed to see if small lesions shown on the other imaging studies could be identified in retrospect.Results The 12 men and four women had an average age of 58 years (range 30–69 years). All 16 patients had an established diagnosis of multiple myeloma, with average duration of disease, from time of initial diagnosis to review, of 30 months (range 6 months to 11+ years). The FDG PET/CT scans revealed a total of 104 sites (90 in bone, 14 soft tissue) that were suspicious for neoplastic activity based on a standardized uptake value (SUV) greater than 2.5. Fifty-seven of these sites (55%) were new or previously undetected. The other imaging studies (X-ray, CT, MR) and clinical information confirmed the other 47 areas but also revealed 133 other small skeletal lesions. Six of these 133 additional lesions showed mild FDG uptake on re-review of the PET/CT scans. The FDG PET/CT findings led to management changes in 9/16 patients. MR imaging revealed five cases of diffuse bone involvement (four spine, one scapula) that were not evident by FDG PET/CT.Conclusion FDG PET/CT scans are useful for the management and staging of myeloma. However, if PET/CT were the sole imaging study done, it would miss many additional small lytic skeletal lesions and could miss diffuse spine involvement.     

FDG PET对肿瘤的评估价值

正电子发射体层(PET)是一种能够识别肿瘤内生化、生理变化的诊断影像技术，FDGPET可明显提高肿瘤诊断的准确性。肿瘤的FDG摄入量是与其内对葡萄糖需求量增加的有增殖能力的肿瘤细胞的代谢率呈正比的。FDG PET在肿瘤应用方面，对肿瘤的分期、分型，复发、转移的早期诊断，坏死与存活组织的鉴别，肿瘤生物特征的预测，及治疗反应的监测作用都得到了广泛承认。     

Role of 18F-fluoride PET/CT in the assessment of multiple myeloma: initial experience

Purpose

The aim of this study was to report our early experience with ¹⁸F-fluoride PET/CT for detecting lesions and evaluate the usefulness of this modality in the assessment of multiple myeloma (MM).

Materials and methods

¹⁸F-fluoride PET/CT and ^99mTc-MDP bone scintigraphy (BS) studies from 7 myeloma patients (4 male and 3 female, mean age 55 years) diagnosed according to standard criteria were reviewed retrospectively. Two reviewers visually and quantitatively analyzed the images and recorded their findings after reaching a consensus. Diagnostic certainty regarding the presence or absence of myeloma lesions was evaluated according to the reference standard consisting of whole-body magnetic resonance imaging and whole-body X-ray.

Results

A total of 93 affected areas were definite according to the reference standard. Of these, 83 affected areas (89 %) were identified on ¹⁸F-fluoride PET/CT, whereas 54 affected areas (58 %) were found on BS. Mean SUVmax in the affected areas was 9.8 ± 3.2 (standard deviation) ranging from 5.0 to 21.2. A total of s17 lesions with bone fracture were also detected by ¹⁸F-fluoride PET/CT and 2 lesions (12 %) were negative on BS.

Conclusion

Our result showed that ¹⁸F-fluoride PET was a possible modality to detect areas of lesions in patients with MM.     

FDG PET in patients with cancer of an unknown primary

BACKGROUND: This prospective study was undertaken to address the capacity of positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG) to determine the primary tumour site of carcinomas with unknown primary site. PATIENTS AND METHODS: Twenty-five patients with metastases from adenocarcinoma or undifferentiated carcinoma of unknown primary site (CUP) were included prospectively. For all patients, extensive imaging was unsuccessful in localizing the primary site. Patients received 370 MBq of 18F-FDG intravenously, and whole-body images were acquired 60 min after injection. All hot spots that could not be attributed to a metastatic site were considered as the primary tumour. The evaluation of FDG PET data was based on clinical and radiological outcome or surgery if indicated. RESULTS: Twenty-four patients were eligible for analysis. All known metastases were visualized. In six patients, FDG PET showed a primary tumour site which was confirmed by follow-up or surgery. In five patients, the primary tumour site was suggested by FDG PET but not confirmed by clinical outcome. No primary tumour was found in the other patients, with a mean follow-up of 15 months. CONCLUSION: In our series, FDG PET allowed the identification of primary tumour site in one quarter of patients with CUP (6/24). We conclude that FDG PET has a place in the initial staging of these patients.     

Evaluation of FDG PET in patients with cervical cancer.

Although many human cancers can be imaged by 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) and PET, there is little clinical experience with FDG PET in cervical cancer. The purpose of this study was to evaluate the feasibility of FDG PET scans on patients with cervical cancer. METHODS: FDG PET scans were performed on 21 patients with histologically proven uterine cervical cancer (17 newly diagnosed, 4 recurrence). After two levels of transmission scanning, approximately 370 MBq FDG were injected, and dynamic scans over 60 min were obtained at the level of suspected tumors, followed by static scans. Postvoid scans were also obtained in 11 patients to minimize FDG activity in the urinary bladder. FDG uptake was interpreted visually and classified into 4 grades (0 = normal, 1 = probably normal, 2 = probably abnormal and 3 = definitely abnormal). For a semiquantitative index of FDG uptake in tumors, the standardized uptake value (SUV) corrected by predicted lean body mass (SUL) was calculated and compared. The detectability of lymph node metastases by PET was compared with that by CT. RESULTS: Of the 21 newly diagnosed or recurrent cancers, 16 (76%) were detected by FDG PET without use of postvoid imaging (i.e., interpreted as grade 2 or 3). The SULs of tumors ranged from 2.74-13.03, with a mean of 8.15 +/- 3.00 (SUV range 3.68-14.94, mean 10.31 +/- 3.19). There was no significant relationship between the SUL of cervical cancer and the clinical stage. Postvoid FDG PET images substantially reduced the tracer activity in the urinary bladder and improved the visualization of cervical cancers, with three additional cases detected using the postvoid images. In the 11 patients with postvoid imaging, all 11 cancers (100%) were detected. FDG PET detected lymph node metastases in 6 (86%) of 7 patients with known metastases, whereas CT was positive in 4 patients (57%), equivocal in 2 patients (29%) and negative in 1 patient (14%). All PET and CT scans were true-negative in the patients with no lymph node metastases (interpreted as grade 0 or 1 by PET, and as negative by CT). CONCLUSION: These preliminary data demonstrate the feasibility of FDG PET imaging in patients with cervical cancer. FDG PET appears to be promising for detecting untreated or recurrent cervical cancers and lymph node metastases, although the excreted FDG in the urine remains problematic in some cases.     

State of the art imaging of multiple myeloma: Comparative review of FDG PET/CT imaging in various clinical settings

18-Flurodeoxyglucose Positron Emission Tomography with computed tomography (FDG PET/CT) and Magnetic Resonance Imaging (MRI) have higher sensitivity and specificity than whole-body X-ray (WBXR) survey in evaluating disease extent in patients with multiple myeloma (MM). Both modalities are now recommended by the Durie–Salmon Plus classification although the emphasis is more on MRI than PET/CT. The presence of extra-medullary disease (EMD) as evaluated by PET/CT imaging, initial SUV_max and number of focal lesions (FL) are deemed to be strong prognostic parameters at staging. MRI remains the most sensitive technique for the detection of diffuse bone marrow involvement in both the pre and post-therapy setting. Compression fractures are best characterized with MRI signal changes, for determining vertebroplasty candidates. While PET/CT allows for earlier and more specific evaluation of therapeutic efficacy compared to MRI, when signal abnormalities persist years after treatment. PET/CT interpretation, however, can be challenging in the vertebral column and pelvis as well as in cases with post-therapy changes. Hence, a reading approach combining the high sensitivity of MRI and superior specificity of FDG PET/CT would be preferred to increase the diagnostic accuracy. In summary, the established management methods in MM, mainly relying on biological tumor parameters should be complemented with functional imaging data, both at staging and restaging for optimal management of MM.     

Value of whole-body FDG PET in management of lung cancer

18F-fluorodeoxyglucose (FDG) PET imaging provides physiologic and metabolic information that characterizes lesions that are indeterminate by CT. FDG PET imaging is sensitive to the detection of lung cancer in patients who have indeterminate lesions on CT, whereas low grade malignancy such as bronchioloalveolar carcinoma and carcinoid may be negative on FDG PET. The specificity of PET imaging is less than its sensitivity because some inflammatory processes, such as active granulomatous infections, avidly accumulate FDG. This possibility should be kept in mind in the analysis of PET studies of glucose metabolism aimed at differentiating malignant from benign solitary pulmonary nodules. FDG uptake is considered to be a good marker of cell differentiation, proliferative potential, aggressiveness, and the grade of malignancy in patients with lung cancer. FDG PET accurately stages the distribution of lung cancer. Several studies have documented the increased accuracy of PET compared with CT in the evaluation of the hilar and mediastinal lymphnode status in patients with lung cancer. Whole-body PET studies detect metastatic disease that is unsuspected by conventional imaging. Management changes have been reported in up to 41% of patients on the basis of the results of whole-body studies. Whole-body FDG PET is also useful for the detection of recurrence. Several studies have indicated that the degree of FDG uptake in primary lung cancer can be used as an independent prognostic factor. Thus, whole-body FDG PET is clinically very useful in the management of lung cancer.     

FDG PET imaging in patients with pathologically verified dementia.

The purpose of this study was to confirm with pathologic verification 2 beliefs related to Alzheimer's disease (AD): (a) the long-standing impression that bilateral temporo-parietal hypometabolism, as noted on FDG PET imaging, is the metabolic abnormality associated with Alzheimer's disease (AD) and (b) that the sensitivity, specificity, and diagnostic accuracy of the metabolic pattern of bilateral temporo-parietal hypometabolism allows differentiation between other degenerative causes of dementia. METHODS: Twenty two individuals (8 women, 14 men) with difficult-to-characterize memory loss or dementia (using standard clinical criteria), and who eventually received pathologic confirmation of diagnosis, were evaluated. FDG PET brain scans were obtained and visually graded by an experienced nuclear medicine physician as to the presence of classic bilateral temporo-parietal hypometabolism as seen in Alzheimer's type dementia. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the metabolic pattern of bilateral temporo-parietal hypometabolism were determined using pathologic diagnosis as the gold standard. RESULTS: The clinical diagnosis of possible or probable AD was determined as the primary cause of dementia in 12 patients. The sensitivity and specificity of the clinical diagnosis for probable AD were 63% and 100%, respectively. The sensitivity and specificity of the clinical diagnosis for possible and probable AD were 75% and 100%, respectively. The sensitivity, specificity, and diagnostic accuracy of bilateral temporo-parietal hypometabolism being associated with AD were 93%, 63%, and 82%, respectively. CONCLUSION: This study confirms that bilateral temporo-parietal hypometabolism is indeed the classic metabolic abnormality associated with AD. Furthermore, in individuals with dementia whose FDG PET scans indicated a metabolic pattern other than bilateral temporo-parietal hypometabolism, a cause of dementia other than AD should be suspected. These observations may be of clinical importance in differentiating dementia syndromes. The sensitivity, specificity, and diagnostic accuracy of FDG PET are acceptable as tests to be used in the evaluation of dementia and particularly to confirm the clinical suspicion of AD.